An investigation of the DAM mutant chicken line characterized by postnatal amelanosis and serious visual problems will be continued. Developmental studies utilizing unilaterally enucleated chicks will be expanded to include more chicks and shorter intervals between enucleation age groups, plus collection of weekly feather germ samples, to provide information on temporal relationships between choroidal melanocyte destruction, inflammatory cell invasion and the feather amelanosis status. The type of inflammatory cells associated with choroidal pigment changes will be characterized. An embryo optic transplant technique will be employed to help clarify relationships between the cutaneous and choroid pigment defects as well as the blindness. Studies on the effects of bursectomy and thymectomy on the amelanosis and eye defect will be continued. An attempt will be made to determine whether or not a meningeal irritation accompanies the onset of the defect, as occurs in the Vogt-Koyanogi-Harada syndrome in humans. Studies on the genetic relationship between the feather amelanosis and the related eye disease will be continued utilizing two sublines, both selected for feather amelanosis, but for different visual status.